1. Field of the Invention
The present invention relates to means for reducing power consumption of an information storage device.
2. Description of the Related Art
To increase the data transfer rate when reading or writing data from or into a medium or to improve the positional precision in servo control in accordance with the increased recording density, the power consumption of information storage devices, such as magnetic disk units, is increasing. When developing magnetic disk units replacing known disk units, the power consumption in accordance with the basic specifications of replacing magnetic disk units should be smaller than or equivalent to that of known magnetic disk units. Accordingly, it is necessary to reduce the power consumption by performing power saving more actively than ever.
In known magnetic disk units, during a seek operation, a formatter or an error checking and correction (ECC) unit continues to operate even if such an operation is not necessary, thereby increasing the power consumption.
One basic technology for reducing the power consumption is to set reading/writing circuits disposed on a data transfer path to be a low power consumption state (clock output is suspended) during a seek operation, as disclosed in Japanese Unexamined Patent Publication (Kokai) No. 5-12781.
In the invention of the above publication, however, even if the supply of the clock to the formatter or the ECC unit is restarted after the seek operation is finished, the read/write operation cannot be performed immediately since a certain time is required to restart the formatter or the ECC unit.